Author
N. Hummadi
Bio: N. Hummadi is an academic researcher from Imperial College London. The author has contributed to research in topics: Quantum chromodynamics & Bar (music). The author has an hindex of 4, co-authored 6 publications receiving 39 citations.
Topics: Quantum chromodynamics, Bar (music), Lepton, Beauty, Spectrometer
Papers
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11 Sep 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the authors describe the detectors and trigger system used in the CERN WA92 experiment, which was designed to study the production and decay of beauty particles from 350 GeV/c π − interactions in copper and tungsten targets.
Abstract: We describe the detectors and trigger system used in the CERN WA92 experiment. The experiment was designed to study the production and decay of beauty particles from 350 GeV/ c π − interactions in copper and tungsten targets. Charged particle tracking is performed using the omega spectrometer. Silicon microstrip detectors are used to provide precise tracking information in the region of the production and the decay of heavy-flavoured particles and to trigger on the resulting high impact parameter tracks. The precision of vertex reconstruction corresponds to ±3.7% of the mean B-decay proper lifetime. Lepton and high transverse momentum hadron signals are also used in the trigger, which accepts 23% of B-decays and rejects 98.4% of non-beauty interactions.
16 citations
TL;DR: In this article, a sample of 475 events, in which two charmed-particle decays are observed, is analyzed to determine distributions of twoparticle kinematic variables.
9 citations
TL;DR: In this paper, a sample of 108 triggered events, produced in π−−Cu interactions at 350 GeV/c, were used to identify 26 beauty events, assuming a linear A-dependence, and measured a beauty production cross section integrated over all χF of 5.7−1.1+1.3 (stat.)−0.5+0.6 (syst.) nb/N.
7 citations
7 citations
CERN1
TL;DR: In this article, the WA92 trigger system was designed to collect beauty decay from fixed-target hadronic interactions, which incorporates muon and high P t triggers, and a novel pixel processor that searches for secondary vertices downstream of the target.
Abstract: This report describes the WA92 trigger system which has been designed to collect beauty decays from fixedtarget hadronic interactions. It incorporates muon and high P t triggers, and a novel pixel processor that searches for secondary vertices downstream of the target.
Cited by
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TL;DR: In this article, it was shown that the meson σ and κ mesons exhibit a spectrum of (squared) masses which are proportional to the sum of orbital angular momentum and radial quantum numbers.
716 citations
CERN1
TL;DR: In this paper, the authors review the hadro-production data presently available on open charm and beauty absolute production cross-sections, collected by experiments at CERN, DESY and Fermilab.
129 citations
11 Apr 2015-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The main characteristics of the COMPASS experimental setup for physics with hadron beams are described in this article, which was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state.
Abstract: The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state. Making use of a large part of the apparatus that was previously built for spin structure studies with a muon beam, it also features a new target system as well as new or upgraded detectors. The hadron setup is able to operate at the high incident hadron flux available at CERN. It is characterised by large angular and momentum coverages, large and nearly flat acceptances, and good two and three-particle mass resolutions. In 2008 and 2009 it was successfully used with positive and negative hadron beams and with liquid hydrogen and solid nuclear targets. This paper describes the new and upgraded detectors and auxiliary equipment, outlines the reconstruction procedures used, and summarises the general performance of the setup.
83 citations
TL;DR: In this paper, a systematic calculation for the transition form factors of heavy to light mesons (B, B-s, D, D-s -> pi, K, eta, rho, K*, w, phi) is carried out by using lightcone sum rules in the framework of heavy quark effective field theory.
Abstract: A systematic calculation for the transition form factors of heavy to light mesons (B, B-s, D, D-s -> pi, K, eta, rho, K*, w, phi) is carried out by using light-cone sum rules in the framework of heavy quark effective field theory. The heavy quark symmetry at the leading order of 1/m(Q) expansion enables us to reduce the independent wave functions and establish interesting relations among form factors. Some relations hold for the whole region of momentum transfer. The meson distribution amplitudes up to twist-4 including the contributions from higher conformal spin partial waves and light meson mass corrections are considered. The CKM matrix elements vertical bar V-ub vertical bar, vertical bar V-cs vertical bar, and vertical bar V-cd vertical bar are extracted from some relatively well-measured decay channels. A detailed prediction for the branching ratios of heavy to light meson decays is then presented. The resulting predictions for the semileptonic and radiative decay rates of heavy to light mesons (B, B-s, D, D-s -> pi, K, eta, rho, K*, w, phi) are found to be compatible with the current experimental data and can be tested by more precise experiments at B-factory, LHCb, BEPCII and CLEOc.
62 citations
TL;DR: The spectroscopy of light and heavy mesons is reviewed in this article with emphasis on glueballs, hybrids, and tetraquarks, and a discussion of their properties is given.
Abstract: The spectroscopy of light and heavy mesons is reviewed with emphasis on glueballs, hybrids, and tetraquarks.
56 citations